JPH0718500A - Gold plating method - Google Patents

Abstract

PURPOSE:To provide a gold plating method using a small-sized plating tank and a hot-plate spinner and by which the concn. and temp. are uniformly distributed in a plating soln. during plating by varying the soln. flow. CONSTITUTION:An agitator 4 of magnetic metal is welded to the bottom in a cylindrical vessel 2, a spiral rod 1 is firmly attached to the inner side wall of the vessel 2, the vessel 2 is inserted into a vessel 3 to constitute a plating tank. The agitator 4, cylindrical vessel 2 and spiral rod 1 are simultaneously rotated by using a hot-plate spinner, a plating soln. is spiraled at its upper part to uniformly distribute the concn. and temp. in the soln., and productivity is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a gold electrolytic solution to immerse a sample to be plated in the solution, and applies electric fields that are opposite to each other in the solution and the sample to be plated to deposit a gold film on the sample to be plated. The method is related to gold plating.

[0002]

2. Description of the Related Art When gold plating is carried out, if the concentration of the plating solution or the temperature of the plating solution changes depending on the volume of the gold plating, the roughness of the plating surface and the plating speed will fluctuate, so stirring is an important factor. Conventionally, such gold plating is performed by agitating by sending fine bubbles from the bottom of the plating tank when a large plating tank is used.In a small plating tank, a hot plate having a stirrer at the bottom of the plating tank is used.
Plating is performed while stirring with a spinner.

[0003]

When a small plating bath is used and a hot plate spinner is used, the flow in the liquid becomes a parallel circular motion due to the rotation of the container. Temperature difference and concentration difference easily occur in the lower part. This phenomenon is particularly likely to occur when the plating area immersed in the liquid is asymmetrical between the upper surface in the liquid surface direction and the lower surface in the bottom surface of the plating tank.

In view of these problems, the object of the present invention is to provide a small-sized comparison in which the concentration and temperature distribution in the plating solution during plating are kept constant above and below the object to be plated. The present invention provides a method of gold plating that can change the liquid flow direction at a relatively low cost.

[0005]

As a gold plating method of the present invention, a method of keeping the concentration and temperature in the liquid during plating constant by moving the liquid flow in the plating liquid during plating in a spiral upward direction. Is obtained. That is, according to the present invention, using a gold electrolytic solution, the sample to be plated is immersed in the solution,
In gold plating, which uses a method of depositing a gold film on the sample to be plated by applying opposite electric fields to the sample to be plated in the liquid, a stirrer and a spiral rod are adhered to the inside of the container, and the plating tank is attached to the hot plate spinner. The method of gold plating is characterized in that the liquid flow during plating is agitated upward in a spiral manner by rotating at.

[0006]

When the plating method using the present invention is used, the stirrer and the spiral rod are closely adhered and adhered to the inside of the container, and at the same time, when the container is rotated by the hot plate spinner, the liquid flow of the plating solution during plating is changed. Since it is agitated upward in a spiral shape inside the plating solution, the concentration and temperature distribution in the plating solution are constant at the top and bottom of the object to be plated. Stable gold plating can be performed. In particular, this liquid state management is very effective for a high-speed traveling wave electrode that requires a plated surface to be a mirror surface.

[0007]

[Embodiment 1] FIG. 1 is a perspective view illustrating a gold plating method according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram showing the configuration of the gold plating apparatus of the present invention.

As shown in FIG. 1, a coiled spiral rod 1
Has an outer diameter substantially equal to the inner diameter of the cylindrical container and is adhered to the inner surface of the cylindrical container 2 while being in close contact therewith. Since the hot plate spinner is used, the stirring bar 4 rotated by the hot plate spinner is adhered to the bottom surface of the cylindrical container 2. The cylindrical container for gold plating is a container having a spiral rod 1 adhered to the inside and a stirrer 4 adhered to the bottom. This is put in an inserted container 3 larger than the cylindrical container 2 to fill the cylindrical container 2 and the inserted container 3 with a plating solution. That is, the plating liquid fills the inside of the cylindrical container 2 and the space between the cylindrical container 2 and the inserted container 3, so that the plating liquid filled between the cylindrical container and the inserted container 3 is Acts as a lubricating oil to rotate. This is used as the plating tank 11 in which both the cylindrical container and the container to be inserted, which are shown in FIG. At this time, the Ti—Pt expander electrode 8, the sample 9 to be plated, and the temperature sensor unit 10 of FIG. 2 are placed in the plating tank 11. With a gold plating device arranged in the plating tank 11, a plating solution is stirred by using a hot plate spinner to rotate the plating tank 11, that is, the cylindrical container so that both the concentration and the temperature are constant in the upper and lower parts. To do. That is, the liquid flow of the plating liquid adopts a method of rotating the plating liquid in a spiral direction.

FIG. 2 is an explanatory view showing the structure of a general small gold plating apparatus. The electric current applied from the DC power source 7 is a Ti-Pt expander electrode (hereinafter referred to as an electrode) 8
Is applied to the sample 9 to be plated, which is the plating surface, to deposit gold ions in the plating solution on the plating surface. The inside of the liquid is electrolyzed by the Ti-Pt expander electrode 8 to deposit gold. The structure is such that gold is deposited by such an ion exchange action. Here, what is important is the concentration of the plating solution (uniformization using the present invention) the temperature of the plating solution (monitored by the thermometer 5 and adjusted by the hot plate spinner 12) applied current value (by the ammeter 6) It means that the quality of plating and the plating speed are controlled by monitoring and adjusting with the power supply 7.

In the embodiment of the present invention, the plating tank 11 composed of the cylindrical container 2 and the container 3 to be inserted having the structure shown in FIG. 1 has the structure of the gold plating apparatus shown in FIG. Neutronex 309 was used as the plating solution.
As the plating conditions, plating was performed under the conditions shown in Table 1.

[0011]

[Table 1]

In order to demonstrate the effect of the present invention, a hot plate having a stirrer at the bottom of a conventional plating tank under the same conditions.
The results of comparing the present invention with the conventional method are shown in Table 2, where plating was performed while stirring with a spinner.

[0013]

[Table 2]

As a comparison, when both of them were measured for reflectance with a laser beam having a wavelength of 633 μm, the reflectances at the upper and lower positions of the sample to be plated in FIG. 2 were improved and the effectiveness of the present invention was confirmed. confirmed.

[0015]

As is apparent from the above, the gold plating apparatus using the present invention not only makes the plating state of the sample near the top and bottom of the plating solution uniform, but also improves the reflectance of the plating surface. It was This shows that the concentration and temperature distribution in the liquid during plating are uniform, and it is clear that the present invention is effective for a small plating apparatus. Further, the cost of the gold plating apparatus is much lower than that of the conventional small plating tank, and therefore the productivity is also good.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a plating tank used in an embodiment of the present invention.

FIG. 2 is an overall view of a gold plating apparatus used in an embodiment of the present invention.

[Explanation of symbols]

1 Spiral rod (cross section may be square or round) 2 Cylindrical container 3 Inserted container 4 Stirrer 5 Thermometer 6 Ammeter 7 Power supply (direct current) 8 Ti-Pt expander electrode (+) 9 Plated sample ( -) 10 Thermometer sensor section 11 Plating tank 12 Hot plate spinner (controlling temperature and stirring rotation speed)

Claims (1)

[Claims] 1. In gold plating, a method of depositing a gold film on a sample to be plated by immersing the sample to be plated in the solution using a gold electrolytic solution and applying an electric field that is opposite to the inside of the solution and the sample to be plated A method of gold plating, characterized in that a stirrer and a spiral rod are brought into close contact with the inside of the container and the plating tank adhered thereto is rotated by a hot plate spinner to spirally stir the liquid flow during plating upward.